Subject: Re: [PATCH] Allow fragmentation of VLAN packets traversing a bridge.

From: Patrick McHardy <[email-masked]>
Date: Fri, 17 Apr 2009 17:57:19 +0200

Saikiran Madugula wrote:
> br_nf_dev_queue_xmit only checks for ETH_P_IP packets for fragmenting but not
> VLAN packets. This results in dropping of large VLAN packets. This can be
> observed when connection tracking is enabled. Connection tracking re-assembles
> fragmented packets, and these have to be re-fragmented when transmitting out.
> 
> Signed-off-by: Saikiran Madugula <[email-masked]>
> ---
>  net/bridge/br_netfilter.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/net/bridge/br_netfilter.c b/net/bridge/br_netfilter.c
> index 3953ac4..941f702 100644
> --- a/net/bridge/br_netfilter.c
> +++ b/net/bridge/br_netfilter.c
> @@ -790,7 +790,7 @@ static unsigned int br_nf_local_out(unsigned int hook, struct sk_buff *skb,
>  
>  static int br_nf_dev_queue_xmit(struct sk_buff *skb)
>  {
> -	if (skb->protocol == htons(ETH_P_IP) &&
> +	if ((skb->protocol == htons(ETH_P_IP) || IS_VLAN_IP(skb)) &&
>  	    skb->len > skb->dev->mtu &&
>  	    !skb_is_gso(skb))
>  		return ip_fragment(skb, br_dev_queue_push_xmit);

Please add an additional check for skb->nfct != NULL to make sure
that this only refragments packets defragmented by conntrack.